Friday June 24, 2022
PhysOrg —
Floodplains must contain a variety of fish habitats, among other things, to restore river fish biodiversity. This is the result of a large-scale study conducted by Wageningen University & Research (WUR) in collaboration with Rijkswaterstaat, which is published in Science of the Total Environment (STOTEN). Additionally, the extent to which the restored floodplain is connected to the river determines its success as a nursery.
Between 2017 and 2020, Ph.D. candidate Twan Stoffers studied the species diversity and abundance of typical river fish in 46 restored floodplains along the major rivers in the Netherlands. “Floodplains are spawning and nursery grounds for river fish,” explains Stoffers. “As a result, optimizing these nurseries is critical for the restoration of biodiversity in our rivers. The degree of connectivity with the river determines whether a floodplain is successful as a nursery. When a floodplain is connected all year, you’ll observe high biodiversity and a lot of fishes.”
Habitat mosaic
Another important feature of restored floodplains for recovering biodiversity is the presence of a diverse variety of fish habitats. This might range from stagnant water with aquatic plants and overhanging willows to oxygenated fast-flowing water with cobbles and boulders. River fish species have different requirements for the environment in which they grow. The highest species diversity, up to 22 unique species per floodplain, is found in places with a mosaic of habitats.